The South Pacific currency, favorites of so-called carry trades, rose as the government agreed to lend as much as $85 billion to the country's biggest insurer and Barclays Plc, the U.K.'s third-biggest bank, agreed to acquire the North American investment-banking unit of Lehman Brothers Holdings Inc.
The Australian dollar rose 1.2 percent to 80.04 U.S. cents at 5:05 p.m. in Sydney from 79.08 cents late in Asia yesterday. It climbed 2.8 percent to 84.70 yen from 82.38 yen yesterday.
The Australian currency has fallen 19 percent against the dollar since reaching a 25-year high on July 16 and 17 percent versus the yen.
The Bank of Japan kept its overnight lending rate at 0.5 percent today and the Federal Reserve left its benchmark rate at 2 percent yesterday. Interest rates are 7 percent in Australia and 7.5 percent in New Zealand, making them favorites with investors seeking higher returns.